package server;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.Node;
import org.dom4j.io.SAXReader;
import server.mapper.Context;
import server.mapper.Host;
import server.mapper.Mapper;
import server.mapper.Wrapper;

import java.io.*;
import java.net.MalformedURLException;
import java.net.ServerSocket;
import java.net.Socket;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.*;

/**
 * Minicat的主类
 */
public class Bootstrap {

    /**
     * 定义socket监听的端口号
     */
    private int port;

    private Mapper mapper = new Mapper();

    /**
     * Minicat启动需要初始化展开的一些操作
     */
    public void start() throws Exception {

        loadServerConfig();

        // 定义一个线程池
        int corePoolSize = 10;
        int maximumPoolSize = 50;
        long keepAliveTime = 100L;
        TimeUnit unit = TimeUnit.SECONDS;
        BlockingQueue<Runnable> workQueue = new ArrayBlockingQueue<>(50);
        ThreadFactory threadFactory = Executors.defaultThreadFactory();
        RejectedExecutionHandler handler = new ThreadPoolExecutor.AbortPolicy();


        ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(
                corePoolSize,
                maximumPoolSize,
                keepAliveTime,
                unit,
                workQueue,
                threadFactory,
                handler
        );





        /*
            完成Minicat 1.0版本
            需求：浏览器请求http://localhost:8080,返回一个固定的字符串到页面"Hello Minicat!"
         */
        ServerSocket serverSocket = new ServerSocket(port);
        System.out.println("=====>>>Minicat start on port：" + port);

        /*while(true) {
            Socket socket = serverSocket.accept();
            // 有了socket，接收到请求，获取输出流
            OutputStream outputStream = socket.getOutputStream();
            String data = "Hello Minicat!";
            String responseText = HttpProtocolUtil.getHttpHeader200(data.getBytes().length) + data;
            outputStream.write(responseText.getBytes());
            socket.close();
        }*/


        /**
         * 完成Minicat 2.0版本
         * 需求：封装Request和Response对象，返回html静态资源文件
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();

            // 封装Request对象和Response对象
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());

            response.outputHtml(request.getUrl());
            socket.close();

        }*/


        /**
         * 完成Minicat 3.0版本
         * 需求：可以请求动态资源（Servlet）
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();

            // 封装Request对象和Response对象
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());

            // 静态资源处理
            if(servletMap.get(request.getUrl()) == null) {
                response.outputHtml(request.getUrl());
            }else{
                // 动态资源servlet请求
                HttpServlet httpServlet = servletMap.get(request.getUrl());
                httpServlet.service(request,response);
            }

            socket.close();

        }
*/

        /*
            多线程改造（不使用线程池）
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            RequestProcessor requestProcessor = new RequestProcessor(socket,servletMap);
            requestProcessor.start();
        }*/


        System.out.println("=========>>>>>>使用线程池进行多线程改造");
        /*
            多线程改造（使用线程池）
         */
        while (true) {

            Socket socket = serverSocket.accept();
            RequestProcessor requestProcessor = new RequestProcessor(socket, mapper);
            //requestProcessor.start();
            threadPoolExecutor.execute(requestProcessor);
        }


    }


    private void loadServerConfig() {
        InputStream resourceAsStream = this.getClass().getClassLoader().getResourceAsStream("server.xml");
        SAXReader saxReader = new SAXReader();

        try {
            Document document = saxReader.read(resourceAsStream);
            Element rootElement = document.getRootElement();

            Element serviceElement = (Element) rootElement.selectSingleNode("Service");
            Element connectorElement = (Element) serviceElement.selectSingleNode("Connector");
            port = Integer.valueOf(connectorElement.attributeValue("port"));

            List<Node> hostElements = rootElement.selectNodes("Service//Engine//Host");
            for (Node node : hostElements) {
                Element hostElement = (Element) node;
                Host host = new Host();
                host.setName(hostElement.attributeValue("name"));
                host.setAppBase(hostElement.attributeValue("appBase"));
                loadContexts(host);
                mapper.addHost(host);
            }


        } catch (DocumentException | FileNotFoundException | MalformedURLException e) {
            e.printStackTrace();
        }
    }

    private void loadContexts(Host host) throws FileNotFoundException, MalformedURLException {
        Path userDir = Paths.get(System.getProperty("user.dir"), "minicat");
        File appBaseDir = new File(userDir.toFile(), host.getAppBase());
        for (File docBase : appBaseDir.listFiles()) {
            if (docBase.isFile()) {
                continue;
            }
            File[] files = docBase.listFiles((dir, name) -> "web.xml".equals(name));
            if (files == null || files.length == 0) {
                continue;
            }
            File webFile = files[0];
            List<Wrapper> wrappers = loadServlet(new FileInputStream(webFile));
            Context context = new Context();
            context.setContextPath('/' + docBase.getName());
            for (Wrapper wrapper : wrappers) {
                context.addWrapper(docBase, wrapper);
            }
            host.addContext(context);
        }
    }

    /**
     * 加载解析web.xml，初始化Servlet
     *
     * @return
     */
    private List<Wrapper> loadServlet(InputStream resourceAsStream) {
        List<Wrapper> wrappers = new ArrayList<>();
        SAXReader saxReader = new SAXReader();

        try {
            Document document = saxReader.read(resourceAsStream);
            Element rootElement = document.getRootElement();

            List<Element> selectNodes = rootElement.selectNodes("//servlet");
            for (int i = 0; i < selectNodes.size(); i++) {
                Element element = selectNodes.get(i);
                // <servlet-name>lagou</servlet-name>
                Element servletnameElement = (Element) element.selectSingleNode("servlet-name");
                String servletName = servletnameElement.getStringValue();
                // <servlet-class>server.LagouServlet</servlet-class>
                Element servletclassElement = (Element) element.selectSingleNode("servlet-class");
                String servletClass = servletclassElement.getStringValue();


                // 根据servlet-name的值找到url-pattern
                Element servletMapping = (Element) rootElement.selectSingleNode("/web-app/servlet-mapping[servlet-name='" + servletName + "']");
                // /lagou
                String urlPattern = servletMapping.selectSingleNode("url-pattern").getStringValue();
                Wrapper wrapper = new Wrapper();
                wrapper.setUrlPattern(urlPattern);
                wrapper.setServletName(servletName);
                wrapper.setServletClass(servletClass);
                wrappers.add(wrapper);
            }


        } catch (DocumentException e) {
            e.printStackTrace();
        }

        return wrappers;
    }


    /**
     * Minicat 的程序启动入口
     *
     * @param args
     */
    public static void main(String[] args) {
        Bootstrap bootstrap = new Bootstrap();
        try {
            // 启动Minicat
            bootstrap.start();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
